import {
  ViewPlugin,
  EditorView,
  Decoration,
  DecorationSet,
  MatchDecorator,
  WidgetType,
  ViewUpdate,
} from '@codemirror/view';
import { Extension, Range } from '@codemirror/state';
import { syntaxTree } from '@codemirror/language';

const pathStr = `<svg viewBox="0 0 1024 1024" width="16" height="16" fill="currentColor"><path d="M607.934444 417.856853c-6.179746-6.1777-12.766768-11.746532-19.554358-16.910135l-0.01228 0.011256c-6.986111-6.719028-16.47216-10.857279-26.930349-10.857279-21.464871 0-38.864146 17.400299-38.864146 38.864146 0 9.497305 3.411703 18.196431 9.071609 24.947182l-0.001023 0c0.001023 0.001023 0.00307 0.00307 0.005117 0.004093 2.718925 3.242857 5.953595 6.03853 9.585309 8.251941 3.664459 3.021823 7.261381 5.997598 10.624988 9.361205l3.203972 3.204995c40.279379 40.229237 28.254507 109.539812-12.024871 149.820214L371.157763 796.383956c-40.278355 40.229237-105.761766 40.229237-146.042167 0l-3.229554-3.231601c-40.281425-40.278355-40.281425-105.809861 0-145.991002l75.93546-75.909877c9.742898-7.733125 15.997346-19.668968 15.997346-33.072233 0-23.312962-18.898419-42.211381-42.211381-42.211381-8.797363 0-16.963347 2.693342-23.725354 7.297197-0.021489-0.045025-0.044002-0.088004-0.066515-0.134053l-0.809435 0.757247c-2.989077 2.148943-5.691629 4.669346-8.025791 7.510044l-78.913281 73.841775c-74.178443 74.229608-74.178443 195.632609 0 269.758863l3.203972 3.202948c74.178443 74.127278 195.529255 74.127278 269.707698 0l171.829484-171.880649c74.076112-74.17435 80.357166-191.184297 6.282077-265.311575L607.934444 417.856853z"></path><path d="M855.61957 165.804257l-3.203972-3.203972c-74.17742-74.178443-195.528232-74.178443-269.706675 0L410.87944 334.479911c-74.178443 74.178443-78.263481 181.296089-4.085038 255.522628l3.152806 3.104711c3.368724 3.367701 6.865361 6.54302 10.434653 9.588379 2.583848 2.885723 5.618974 5.355985 8.992815 7.309476 0.025583 0.020466 0.052189 0.041956 0.077771 0.062422l0.011256-0.010233c5.377474 3.092431 11.608386 4.870938 18.257829 4.870938 20.263509 0 36.68962-16.428158 36.68962-36.68962 0-5.719258-1.309832-11.132548-3.645017-15.95846l0 0c-4.850471-10.891048-13.930267-17.521049-20.210297-23.802102l-3.15383-3.102664c-40.278355-40.278355-24.982998-98.79612 15.295358-139.074476l171.930791-171.830507c40.179095-40.280402 105.685018-40.280402 145.965419 0l3.206018 3.152806c40.279379 40.281425 40.279379 105.838513 0 146.06775l-75.686796 75.737962c-10.296507 7.628748-16.97358 19.865443-16.97358 33.662681 0 23.12365 18.745946 41.87062 41.87062 41.87062 8.048303 0 15.563464-2.275833 21.944801-6.211469 0.048095 0.081864 0.093121 0.157589 0.141216 0.240477l1.173732-1.083681c3.616364-2.421142 6.828522-5.393847 9.529027-8.792247l79.766718-73.603345C929.798013 361.334535 929.798013 239.981676 855.61957 165.804257z"></path></svg>`;

export interface HyperLinkState {
  at: number;
  url: string;
}

class HyperLinkIcon extends WidgetType {
  private readonly state: HyperLinkState;
  constructor(state: HyperLinkState) {
    super();
    this.state = state;
  }
  eq(other: HyperLinkIcon) {
    return this.state.url === other.state.url && this.state.at === other.state.at;
  }
  toDOM() {
    const wrapper = document.createElement('a');
    wrapper.href = this.state.url;
    wrapper.target = '_blank';
    wrapper.innerHTML = pathStr;
    wrapper.className = 'cm-hyper-link-icon';
    wrapper.rel = 'nofollow';
    return wrapper;
  }
}

function hyperLinkDecorations(view: EditorView) {
  const widgets: Array<Range<Decoration>> = [];
  for (const range of view.visibleRanges) {
    syntaxTree(view.state).iterate({
      from: range.from,
      to: range.to,
      enter: ({ type, from, to }) => {
        const callExp: string = view.state.doc.sliceString(from, to);
        if (type.name === 'URL') {
          const widget = Decoration.widget({
            widget: new HyperLinkIcon({
              at: to,
              url: callExp,
            }),
            side: 1,
          });
          widgets.push(widget.range(to));
        }
      },
    });
  }
  return Decoration.set(widgets);
}

const linkDecorator = (regexp?: RegExp, matchData?: Record<string, string>, matchFn?: (str: string) => string) =>
  new MatchDecorator({
    regexp: regexp || /\b((?:https?|ftp):\/\/[^\s/$.?#].[^\s]*)\b/gi,
    decorate: (add, from, to, match, view) => {
      const url = match[0];
      let urlStr = matchFn && typeof matchFn === 'function' ? matchFn(url) : url;
      if (matchData && matchData[url]) {
        urlStr = matchData[url];
      }
      const start = to,
        end = to;
      const linkIcon = new HyperLinkIcon({ at: start, url: urlStr });
      add(start, end, Decoration.widget({ widget: linkIcon, side: 1 }));
    },
  });

export type hyperLinkExtensionOptions = {
  regexp?: RegExp;
  match?: Record<string, string>;
  handle?: (value: string) => string;
};

export function hyperLinkExtension({ regexp, match, handle }: hyperLinkExtensionOptions = {}) {
  return ViewPlugin.fromClass(
    class HyperLinkView {
      decorator?: MatchDecorator;
      decorations: DecorationSet;
      constructor(view: EditorView) {
        if (regexp) {
          this.decorator = linkDecorator(regexp, match, handle);
          this.decorations = this.decorator.createDeco(view);
        } else {
          this.decorations = hyperLinkDecorations(view);
        }
      }
      update(update: ViewUpdate) {
        if (update.docChanged || update.viewportChanged) {
          if (regexp && this.decorator) {
            this.decorations = this.decorator.updateDeco(update, this.decorations);
          } else {
            this.decorations = hyperLinkDecorations(update.view);
          }
        }
      }
    },
    {
      decorations: (v) => v.decorations,
    },
  );
}

export const hyperLinkStyle = EditorView.baseTheme({
  '.cm-hyper-link-icon': {
    display: 'inline-block',
    verticalAlign: 'middle',
    marginLeft: '0.2ch',
  },
  '.cm-hyper-link-icon svg': {
    display: 'block',
  },
});

export const hyperLink: Extension = [hyperLinkExtension(), hyperLinkStyle];
